nmt(1)

💖 NAME 💖

nmt — the Osmocom Analog NMT bestie, and all its lore lives at http://osmocom-analog.eversberg.eu/docs/

✨ SYNOPSIS ✨

nmt -k <kanal/channel> [-N 900] -Y <traffic area> | list  [-I 1] [-0 1]
[options] [station_id]

🌍 Global options 🌍

The main-character starter pack. Pick your faves, don't skip the defaults, ok?

• -h, --help — the help. Your safe space. 💖
• --config [~/]<path to config file> — hand over a config file to use. If the path starts with ~/, that path lives in your home dir. Each line in the config file is one option — and no cap, you must not write - or -- on those lines! Default: ~/.osmocom/analog/nmt.conf
• --no-config — even if a config file is sitting right there, we're not using it. Nope. 🙈
• -v, --verbose <level> | <level>,<category>[,<category>[,...]] | list — hit list to get a list of all levels and categories. Verbose level: just the digit of the debug level (default = 3). Verbose level + category: the level digit followed by one or more categories -> if no category is specified, all categories are selected.
• -v, --verbose date — show the date alongside the debug output. timestamp slay. 🕰️
• -k, --kanal <channel>
• -k, --channel <channel>

Channel (German = Kanal) number of the "Sender" (German = Transceiver). Two spellings, same vibe. ✨

• -a, --audio-device hw:<card>,<device>[/hw:<card>.<rec-device>] — sound card and device number (default = hw:0,0). You can specify a different recording device by using /. > Do NOT set this for SDR!
• -s, --samplerate <rate> — sample rate of the sound device (default = 48000).
• -i, --interval 0.1..25 — interval of the processing loop in ms (default = 1.0 ms). Use 10 to drastically reduce CPU usage. If you get buffer underrun, increase the buffer accordingly. 💅
• -b, --buffer <ms> — how many milliseconds are processed in advance (default = 50). A buffer below 10 ms requires a low interval like 0.1 ms.
• -p, --pre-emphasis — enable pre-emphasis if you're directly connected to the oscillator of the transmitter. (No pre-emphasis done by the transmitter.)
• -d, --de-emphasis — enable de-emphasis if you're directly connected to the discriminator of the receiver. (No de-emphasis done by the receiver.)
• --rx-gain <dB> — raise/lower the receiver's RX level by the given gain in dB. (Works with sound card only.)
• --tx-gain <dB> — raise/lower the transmitter's RX level by the given gain in dB. (Works with sound card only.)
• -e, --echo-test — echo test mode, which sends audio back from the mobile phone's microphone to the speaker. (German: 'Blasprobe'.) 🎤
• -c, --call-device hw:<card>,<device>[/hw:<card>.<rec-device>] — sound card and device number for the headset (default = ''). You can specify a different recording device by using /.
• --call-samplerate <rate> — sample rate of the sound device for the headset (default = 48000).
• --call-buffer <ms> — how many milliseconds are processed in advance (default = 50).
• -x, --osmocc-cross — enable built-in call forwarding between mobiles. Be sure to have at least one control channel and two voice channels. Alternatively use one combined control+voice channel and one voice channels. 🫶
• -o, --osmocc-sock — disable built-in call control and offer a socket instead.
• --cc "<osmo-cc arg>" [--cc ...] — pass arguments to the Osmo-CC endpoint. Use -cc help for a description.
• --no-l16 — disable the L16 (linear 16 bit) codec. bye codec. 👋
• -t, --tones 0 | 1 — connect the call on setup/release to provide classic tones towards the fixed network (default = 1).
• -l, --loopback <type> — loopback test: 1 = internal | 2 = external | 3 = echo.
• -r, --realtime <prio> — set prio: 0 to disable, 99 for maximum (default = 0).
• --fast-math — use fast math approximation for slow CPU / ARM based systems. 🐢➡️🐇
• --write-rx-wave <file> — write received audio to the given wave file.
• --write-tx-wave <file> — write transmitted audio to the given wave file.
• --read-rx-wave <file> — replace received audio by the given wave file.
• --read-tx-wave <file> — replace transmitted audio by the given wave file.
• --limesdr — auto-select several required options for LimeSDR.
• --limesdr-mini — auto-select several required options for LimeSDR Mini.

📡 SDR options 📡

For when you're doing the whole software-defined-radio thing. iykyk.

• --sdr-soapy — force the SoapySDR driver.
• --sdr-channel <channel #> — give the channel number for a multi channel SDR device (default = 0).
• --sdr-device-args <args>
• --sdr-stream-args <args>
• --sdr-tune-args <args>

Optional SDR device arguments, separated by comma, e.g. --sdr-device-args <key>=<value>[,<key>=<value>[,...]]

• --sdr-samplerate <samplerate> — sample rate to use with the SDR. By default it equals the regular sample rate.
• --sdr-lo-offset <Hz> — give a frequency offset in Hz to move the local oscillator away from the target frequency. (default = -1000000)
• --sdr-bandwidth <bandwidth> — give the IF filter bandwidth to use. If you don't, the sample rate is used.
• --sdr-rx-antenna <name> — the SDR device's RX antenna name, use list to get a list.
• --sdr-tx-antenna <name> — the SDR device's TX antenna name, use list to get a list.
• --sdr-clock-source <name> — the SDR device's clock source name, use list to get a list.
• --sdr-rx-gain <gain> — the SDR device's RX gain in dB (default = 0.0).
• --sdr-tx-gain <gain> — the SDR device's TX gain in dB (default = 0.0).
• --write-iq-rx-wave <file> — write received IQ data to the given wave file.
• --write-iq-tx-wave <file> — write transmitted IQ data to the given wave file.
• --read-iq-rx-wave <file> — replace received IQ data by the given wave file.
• --read-iq-tx-wave <file> — replace transmitted IQ data by the given wave file.
• --sdr-swap-links — swap RX and TX frequencies for loopback tests over the air.
• --sdr-timestamps 1 | 0 — use TX timestamps on a UHD device. (default = 1)

📞 Network specific options 📞

The ones that actually decide whether your phone vibes with the network. Choose wisely bestie.

• -N, --nmt-system 450/900 — give the NMT type as the first parameter. (default = 450) > Note: this option must be given at first!
• -T, --channel-type <channel type> | list — give the channel type, use list to get a list. (default = CC/TC)
• -P, --ms-power <power level> — give the power level of the mobile station 0..3. (default = 1) NMT-450: 3 = 15 W / 7 W (handheld), 2 = 1.5 W, 1/0 = 150 mW. > Note: a power level < 2 causes the mobile to search longer for a cell.
• -Y, --traffic-area <traffic area> | list — give the short country code and traffic area separated by a comma. (Example: give SE,1 for Sweden, traffic area 1.) Add ! to force a traffic area that is not supported by the country. (Example: give B,12! for Belgium, traffic area 12.) Use list to get a list of available country code names.

NOTE: MUST MATCH WITH YOUR ROAMING SETTINGS IN THE PHONE!

Your phone will not connect if the country code is different! 😭

• -A, --area-number <area no> | 0 — give area number 1..4, or 0 for no area number. (default = 0)
• -C, --compandor 1 | 0 — make use of the compandor to reduce noise during a call. (default = 1)
• -0, --supervisory 1..4 | 0 — use supervisory signal 1..4 to detect loss of signal from the mobile station, use 0 to disable. (default = 1)
• -S, --smsc-number <digits> — if this number is dialed, the mobile is connected to the SMSC (Short Message Service Center). (default = 767)
• -I, --caller-id 1 | 0 — if set, the caller ID is sent while ringing the phone. (default = 0)
• -U, --clock 1 | 0 — if set, the current time is transmitted with CC. (default = 0) > Note that this works only with pure CC, not with combined CC+TC.
• station_id — give 7 digits of station ID, so you don't need to enter it for every start of this application. Give 7 digits for the NMT number (1st digit = country code). 🎀

🎹 Keys, because you're the main character 🎹

Press digits '0'..'9' and then the 'd' key to dial towards a mobile station. Press the 'h' key to hangup. Press the 'w' key to toggle display of RX wave form. Press the 'c' key to toggle display of channel status. Press the 'm' key to toggle display of measurement value. Press the 'q' key to toggle display of RX I/Q vector. Press the 's' key to toggle display of RX spectrum. Press the 'b' key to remove DC level. 💅✨

and that's the whole page, bestie!! it lives in the General Commands Manual, and the little tag at the bottom of the page just says nmt(1) — that's the manual name right back atcha, iconic circular moment. 🦋 go forth and transmit, you absolute legend. 🫶💖